Heating element and method of making the same



Se t. 192

p 7 v. A. BOKER HEATING ELEMENT AND METHOD OF MAKING THE SAME Filed Aug. 18, 1924 3144:4114 *o'o, V07 .4 60x52,

Patented 7 Sept. 13, 1927. I

yUNITED STAT 'VI'IUS A. IBOKER, OF MINNEAPOLIS, MINNESOTA.

HEATING ELEM NT AND METHOD or MAKING THE SAME.

Application filed August 18,1924. Serial No. 732,728.

One object of my invention is to provide a strong rigid type of heat element that will stand a maximum of abuse. I

Another object is to provide a heating element in'which the heat coil and terminals are formed of a single continuous piece of wire.

Another object is to provide in a heating element, a core of such type that ametal shell may be solidly joined thereto and the conductor perfectly insulated therefrom.

Another object is to provide an improved method of forming the terminals and conductor of a heating element of a single piece of wire with no resultant slack wire.

With these and incidental objects in. view, the invention consists of certain novel features and combination of parts, the essential elements'of which are hereinafter described with reference to the drawing acv companying the specification and also a certain new method of producing the device described herein.

In the drawing, Figure 1 is a side elevation of my improved heating element with portions of the outer shell broken away. igure 2 is a to view of the same. Figure 3 is a section ta en on the line 33, Figure 2, and Figure 4. is a section taken on the line 4-4, Figure 1. 3

' As shown in the drawing, the core has heads 2 and 3 at either end thereof, the portion between theheads being reduced in cross sectional area.

An aperture 4 is drilled through the head 2 parallel with the axis of the core to allow the bringing out of one end of the w1re through the aperture'to form the terminal, as will later be described.

The axial aperture 5 runs through substantially the entire length of the core, but is met in the head 2 by the inclined aperture 6, which serves to bring out the other terminal. A well or pocket 7 is left in the head 3 for purposes hereinafter described and a radial aperture 8 permits the wire being brought from the exterior of the core to the pocket 7.

This core 2 may be made of any suitable i material, but I have in general preferred to use soapstone, turnin the core as shown and cutting shallow t reads along its surface at 9 to receive thereinthe convolutions of the resistor.

i In applying the conductor to the core, I prefer to form a double loop 10, twisting the free end of the wire back as at 11 and insert the twisted portion into the aperture a, bringing the conductor to the threads 9, in which the resistor is then wound to the opposite end of the core where it is passed through pocket 7.

From the poclset 7 the free end of the Wire is fed through the axial aperture 5 and inclined aperture 6 and then the second termlnal loop 12 is formed and the free end of the wire twisted back as at 13. This twisted portion is then drawn back into the aperture 6 by pulling theslaek into the pocket 7 and the slack is then disposed of by looping and twisting the wire as indieated at 14:, Figure 4.

the radial aperture 8 into the When the resistor has been thus wound and, the terminals thus firmly positioned" by drawing the twisted portions of thewire into the apertures 4 and 6 andtaking up the slack as shown at 14, the resistor is firmly and solidly mounted on the core and without outside protection would stand a veryconsiderable amount of abuse. I

However, to thoroughly protect the' re sistor, I provided the shell 15, which closely fits over the heads-2 and 3, as shown in Figure 1 and this shell is spun ove the head 2, as shown at 16, Figure 1, and a disc 17 is dropped over the end of the head 3 and the end of the shell at 18 is then spun around this disc and also brazed or welded thereto.

This insures the core with its mounted conductor being solidly incased in the shell and prevents any damage from the exterior.

To further insure the protection of the resistor, I sometimes fill the space 19 between the core and the shell and between the heads 2 and 3 with a comminuted refractory insulating substance, for which I sometimes employ the turnings obtained from the forming of the core itself.

When this space is well packed with such a material the resultant element is absolutely solid,'rigid and will stand an almost unlimited amount of abuse.

While I have described my invention and illustrated it in one particular style and method, I do not wish it understood that I limit myself to this particular embodiment as it is evident the invention may be varied in many ways within the scope of the following claims:

I claim:

1. In a heating element, the combination of-a core having integrally formed heads at the ends thereof, one of said heads having intermediate said heads, one end of said resistor extending through said lateral aper ture and the other extending into said pocket and from thence into and through said first mentioned aperture,

2. In e heating element, the combination of a core having heads on either end thereof and threadscut on the intermediate portion thereof and on eperture pessing through seid head parallel with the axis of said core, on axial aperture, an inclined aperture meeting said axial aperture and having a pocket formed at one end thereof, of a resistor wound on the intermediate portion of said core and heving the ends thereof passing through said apertures end formed into reinforced terminals, e portion of said resistor being deposited in the pocket positioned at one end of seid core,

3. In a heating element, the combination with a core having e body. portion and two head portions of a resistor wound oround the body portion of said core and passing through apertures in said core out of one end of said core, the ends of said resistor being formed into reinforced terminal loops, a part of said reinforcement extending into the apertures in said core.

4. In a heating element, the combination with a core which is reduced-intermediate its two ends and threaded over said reduced portion, one end of the core having a lateral aperture opening to the nearer end of the threaded portion, and said core having a long aperture extending substantially throughout its length to connect the said end of the core with the farther end of the threaded portion, a resistor wound upon said threaded portion and having its ends extending through the respective apertures and paired, as terminals, beyond said end of the core, the extreme. end portions of the resistor being twisted heck upon themselves to reinforce the terminals formed thereby, said twisted portionsv of the resistor being contained within said apertures. t 5. The structure set forth in claim 4: in which said core hes e pocket, in the end 0pposite from the terminals, for enclosing a slack portion of the resistor which is redrawn from the iong aperture. Y 6. in a heating element the combination of a core, the major portion of which is threaded, said core having an aperture extending from one end thereof to the nearer end of the threaded portion of the core, said 0 core having a pocket in the other end thereof and at long aperture extending from said pocket through the core and to the opposite end thereof, said pocket Communicating with the threaded portion of the core adjacent 7G thereto, a resistor wound upon said threaded portion and having one end projected through said first mentioned aperture, the other end of the resistor being projected throughthe pocket and said long aperture and out of the core near the first mentioned end of the resistor, said resistor ends being formed into terminals by being looped and twisted upon themselves, the twisted portions b'ein within said apertures so as to reinforce t e terminals. VITUS A. B'OKER. 

